1. Field of the Invention
This invention relates generally to computers, and in particular, to testing of computer peripheral interface devices.
2. Description of the Related Technology
Personal computers are becoming more prevalent in the work place, and with more and more people depending on their livelihoods from the use thereof. Increased sophistication of the personal computers coupled with the computer user's dependency thereon have driven the computer manufacturers to improve computer system reliability and mean time to repair when a problem occurs.
The computer system comprises a plurality of subsystems and peripherals that may be tested individually to determine which part of the computer system is causing the malfunction. Once the general area of the problem is ascertained, a more specific subsystem or peripheral test may be utilized to pin point the problem and enable the computer service technician to repair same.
When two peripheral interface devices share the same or similar functionality such as, for example, a system motherboard video interface and an expansion video interface adapted for connection to the computer system local bus, testing of one or the other may require removal or disabling of the interface not being tested. As an example, when there is a video system problem the technician must ascertain whether the problem is being caused by the system board interface or the expansion interface. Heretofore, the technician would have to physically remove the expansion interface from the computer system to see if the problem disappeared.
Finding a problem in the computer system, using the aforementioned method of trouble shooting, was extremely labor intensive, time consuming and expensive. In addition, there was always a possibility of creating additional problems by removing and replacing the hardware from the computer system. Ideally, what is needed is a method and apparatus that would allow the testing of subsystems without having to physically disconnect parts of the computer system.
Computer system peripheral manufacturers started implementing embedded diagnostic software or firmware programs that could be utilized to more easily pinpoint the trouble. This enhanced trouble shooting and was extremely effective as computer systems became more sophisticated, and the number and type of peripheral interface devices increased. The inevitable happened, however, when one peripheral interface device interfered with the testing of another peripheral interface device.
One peripheral interface device may interfere with another when running diagnostics on a computer system having a plurality of interface devices, from a variety of different manufacturers, some of which do not behave passively when held in reset. Computer system peripheral devices such as, for example, video controller interfaces may have diagnostic programs embedded within firmware supplied as part of the overall peripheral interface control logic program. The embedded diagnostic programs may, for example, check video memory for proper operation and display color video test patterns for verifying overall video system performance.
Most computer systems are supplied with a video interface controller as an integral part of the system printed circuit board or "motherboard". Various peripheral interfaces are integrated onto the computer system motherboard; however, as new technology is developed, the computer system user may elect to add the newer technology interfaces to the computer system. A recently developed high speed host computer local bus interface has been implemented into present day personal computer systems. This high speed local bus may be utilized for cache memory, communications and high resolution color graphic video. The video adapter utilized on the local bus may conform to the proposed Video Electronics Standards Association standard for advanced local bus video controllers (VESA/VL).
The purpose of the VESA/VL standard is to specify uniform interface, architecture, timing, electrical, and physical characteristics that will allow VESA/VL based products from various different manufacturers to be interchangeable in a computer system. Even with standards such as the VESA/VL, problems arise between various different peripheral interface devices that were not taken into consideration by the applicable standards. Even if a standard does cover a particular compatibility problem, not all manufacturers may entirely comply with the standard. Thus, some way must be found for the computer system itself to control possible erratic behavior between a multitude of different peripheral interface devices during testing or self diagnosis.
What is needed is a way to control the various peripheral interface devices residing within the computer system without having to physically remove any peripherals therefrom. Preferably, the computer system itself will maintain control and have the ability to disable any offending peripheral device not conforming to an applicable interface operating standard or, in the alternative, the aberrant or erratic operation of a peripheral, not covered by an appropriate standard, may nevertheless be effectively disabled so as not to detrimentally interfere during computer system testing.